@charset "UTF-8";
.app {
  width: 80px;
  height: 90px;
  border: 1px solid red;
}

* {
  margin: 0;
  color: pink;
}

.box {
  width: 42px;
}

.box .box1 {
  width: 52px;
}

.box .box1:hover {
  color: red;
}

#aaa h1, #aaa h2, #aaa h3 {
  color: aqua;
}

#b {
  border-style: solid;
  border-width: 100px;
}

.note {
  width: 600px;
  background-color: aqua;
  border: 1px solid red;
}

a {
  color: #501;
  border: 1px solid #ff0;
}

a:hover {
  color: #aa9;
}

/*这是一个注释*/
.error, .arror {
  border: 1px solid red;
  background-color: #ffe;
}

.arror {
  border-width: 3px;
}
